High molecular weight copolyamides containing hydantoin units

ABSTRACT

High molecular weight aromatic copolyamides which contain a small proportion of structural units having hydantoin rings are disclosed. The presence of hydantoin ring units in the copolyamide results in an increased moisture absorption capacity. By using small amounts of hydantoin units, the good physical properties of the corresponding hydantoin-free polyamide are substantially retained while the moisture absorption is significantly increased. Larger amounts of hydantoin units than contemplated (15 mole % and more) do not improve the moisture absorption further and adversely affect the physical properties. The copolyamides are useful in textile applications in which the improved moisture absorption serves to make clothing prepared from such textiles more comfortable.

United States Patent 1191 Wolf et al. [4 1 Dec. 9, 1975 15 HIGH MOLECULAR WEIGHT 3,376,268 4/1968 Preston 260/78 CO O CONTAINING 3,484,407 12/1969 Preston 260/47 3,671,614 6/1972 Kunzel et a1... 260/47 HYDANTOIN UNITS 3,681,282 8/1972 Preston 260/466 [75] Inventors: Gerhard Dieter Wolf; Hans Egon Rum], both of Dormagen; Gfimher FOREIGN PATENTS OR APPLICATIONS Blankenstein, Stommeln; Pete. 2,009,741 9/1971 Germany 260/47 CZ Kleinschmidt, Dormagen; Francis Bentz, Cologne, all of Germany Pnmary Exammer lfester Lee Attorney, Agent, or Farm-Plumley & Tyner [73] Assigneez Bayer Aktiengesellschaft,

LeverkusemBayerwerk, Germany 57 ABSTRACT [22] Filed: May 3, 1974 High molecular weight aromatic copolyamides which contain a small proportion of structural units having [2]] Appl' 466341 hydantoin rings are disclosed. The presence of hydan- Related U.S. Application Data toin ring units in the copolyamide results in an in- [63] Continuation-impart of Ser. No. 361,526, May 18, creased moisture b p i p y By using small 1973, abandoned. amounts of hydantoln units, the good physical properties of the corresponding hydantoin-free polyamide 52 U.S. Cl. 260/47 (:2; 260/302; 260/63 R; are substantially retained while the moisture p- 260/65; 260/78 R; 260/D1G 34 tion is significantly increased. Larger amounts of hy- [51] Int. C1. C08G 69/32 dantoin units n n mp 5 l and [58] Field of Search 260/47 C2, 63 R, 78 R, more) do not improve the moisture absorption further 260/65, DIG, 34 and adversely affect the physical properties. The copolyamides are useful in textile applications in [56] References Cit d which the improved moisture absorption serves to UNITED STATES PATENTS make clothing prepared from such textiles more com- 3,324,086 6/1967 Raleigh 260/78 fonable' 3,354,120 11/1967 Bach et a1 260/47 10 Claims, No Drawings HIGH MOLECULAR WEIGHT COPOLYAMIDES CONTAINING I-IYDANTOIN UNITS which contain a small proportion of co-condensed units containing hydantoin rings.

It is known that fully aromatic polyamides, which generally have good thermal properties and are comparatively incombustible, have only a limited capacity for absorbing and retaining water. The moisture absorption capacity (at 65% relative humidity and 2lC) of poly-m-phenylene-isophthalamide is given as 4.5%. One of the factors which makes textiles comfortable to wear is a good water absorption capacity of the fibers used. It is therefore desirable that fully aromatic polyamides which are used in textile applications, for example as protective clothing against heat, fire, acids and alkalies (underwear, socks, gloves, anoraks, suits, and uniforms), should have a high moisture absorption capacity in order that they should be comfortable to wear. A moisture absorption capacity of 9% or more is considered desirable for wear comfort.

Compared with the corresponding fully aromatic polyamides without hydantoin units, the copolyamides of this invention containing hydantoin units are distinguished by higher moisture absorption and substantially improved solubility in polar organic solvents, which is an advantage in the production of threads and fibers.

Copolyamides containing hydantoin units are described in German Offenlegungsschrift No. 2,009,741 the specific embodiments of which relate to copolyamides containing relatively high amounts of hydantoin units compared to the copolyamides of this invention. However, it has been unexpectedly found that the hydantoin content of the German Offenlegungsschrift can be advantageously reduced to obtain copolyamides which have a better moisture absorption, higher crystallinity and therefore better physical properties, and which are more economically to produce because of the lower proportion of the expensive hydantoin component.

Accordingly, this invention relates to copolyamides containing less than mol percent of hydantoin units but sufficient to produce a copolyamide having a moisture absorption of at least 9%. It is also preferred that the amount of hydantoin units be such that a detectable amount of crystallinity, characteristic of the corresponding homopolymer, be retained. The exact molar proportions of copolyamide components necessary to achieve these objectives varies somewhat with the chemical structure of the copolyamide components but in any case, the copolyamide comprises less than 15% mol percent of hydantoin units, generally in the range of 1-l2 mol percent. Usually, at least about 5 mol percent of hydantoin is needed to provide the desired moisture absorption of 9%. Preferably, about 59.5 mol percent of hydantoin units are used and most preferably 5-9 mol percent.

Crystallinity can be determined from X-ray wide-angle diagramccd in H. P. Klug and L. E. Alexander, X-Ray Diffraction Procedures, J. Wiley and Sons, 6 Printing, 1970.

The copolyamides which have the highest moisture absorption capacity coupled with good physical properties are those in which only a small proportion of the diamine component, namely 5 to 9.5 mol percent has been replaced by hydantoin diamine units.

This invention therefore broadly relates to high molecular weight aromatic copolyamides which have a moisture absorption of at least 9% and which contain less than 15 mol percent of structural units which contain hydantoin rings, represented by the general formula Z represents a single bond or the group -HyX and X and Y may be the same or different and represent bivalent aromatic groups which consist of one or more condensed rings or several aromatic rings which are linked together by single bonds or by bridge members such as O,

or PIN-S0 or their halogen, C to C alkyl, N0 or CN substitution products and Hy represents a bivalent hydantoin ring of the formula c l o R represents a hydrogen atom, C to C alkyl, cycloalkyl or an optionally substituted phenyl group, and

Ar represents a bivalent aromatic group which consists of one or more condensed or several aromatic rings which are linked together by single bonds or by bridge members such as O, S, SO

or their halogen, C to C, alkyl, N0 or CN substitution products, and more than mol percent of structural units of the general formula HNAr'-NHOCAr-CO omatic diamines corresponding to the general formula H,NAr'-NH, v)

in which Ar had the meaning defined above.

3 4 The following diamines are given as examples: m- The second component consists of one or more diphenylene diamine, p-phenylene diamine, 4,4'- amines correspondin to the general formula diaminodiphenylether, 4,4'-diaminodiphenylsulphide, jh Y 2,6-diaminoaphthalene, 2,7-diaminonaphthalene, benm which X, Y and "1/ have the meamngs Indicated zidine, 4,4'-diaminocliphenylmethane, 4,4- 5 abovediaminodiphenylsulphone, 3,3-diaminobenzophenone, l,4-bis-(p-aminophenoxy)-benzene and 4,4'-bis- The following are given as examples of such di- (p-aminophenoxy)-diphenylsulphone. amines:

P 40 CH -C C l l H N- --O- -N\ /N- --NH O on 0 H N- -N These diamines are added in the proportions indicated above in order to achieve a moisture absorption of 9% and at the same time to preserve at least some of the crystalline character of the corresponding homopolyamide.

These diamines which contain hydantoin rings may be prepared in accordance with methods already previously proposed by the present applicants, for example as follows:

Aromatic diamines which contain a hydantoin ring may be obtained by reacting N-substituted a-amino acid nitriles or esters with aromatic isocyanates in a molar ratio of 1:1 in inert solvents with ring closure of the resulting ureas to produce hydantoin derivatives, followed by reduction of the nitro groups.

Preparation of these diamines may be carried out in such a manner that both the N-substituted a-aminocarboxylic acid nitriles or esters and the aromatic isocyanates from the start contain each a nitro group or alternatively one or both nitro groups may be introduced by nitration of the hydantoin derivatives.

Suitable aromatic diamines in which two hydantoin so rings separated by aromatic groups are situated between the two aromatic amino groups are, for example, those diamines which can be prepared in known manner by reacting N-substituted a-aminocarboxylic acid nitriles or esters which contain a nitro group of the formula with aromatic diisocyanates of the formula OCN-Y-NCO 65 in which X, Y and R have the meanings defined above 7 8 These diamines may also be obtained by a similar re- One feature which is particularly important is the action path by reacting aromatic isocyanates which substantial increased moisture absorption capacity of contain a nitro group, represented by the formula the polyamides according to the invention, which O*NXNCO makes them particularly suitable for use as fibres in the with aromatic componds which contain two aaminocarboxylic acid nitrile groups or two a-aminocarboxylic acid ester groups of the formula textile sector for the manufacture of protective clothing (underwear, socks, gloves, suits) to protect against fire, heat, acid and alkalies.

i R l NC-C-NHY-NHCCN or R'OOCTNHY-NH-CCOOR' l R l in which Y, X, R and R have the meanings defined The following Table shows that copolyamides which above, in a molar ratio of 2 1, followed by ring closure contain 5 to 9.5 mols percent of hydantoin units have a and reduction of the nitro groups. particularly high moisture absorption capacity. The di- The third component consists of aromatic dicarbox- 2o amine of the following formula ylic acid dihalides of the general formula HaIOC-ArCO-Hal. (Ill) in which Hal represents Cl or Br and Ar has the mean- 9 5 o ing indicated above. The following are given as exam- CH -0 C ples of such aromatic dicarboxylic acid dihalides: 150- I phthalic acid dichloride, terephthalic acid dichloride, H diphenyl-4,4'-carboxylic acid dichloride, naphthalene- 2 2 l,5-dicarboxylic acid dichloride, naphthalene-2,6-

dicarboxylic acid dichloride, diphenylether-4,4'-dicar- 0 (VIII) boxylic acid dichloride, diphenylsulphone-4,4'-dicarboxylic acid dichloride, benzophenone-4,4'-dicarboxyhe acid dichloride and the corresponding dibromides was d i hi series of i m and alkyland halogen-substitution products of the given acid dihalides.

Polycondensation of the three components described Condensate H,o absorption above is carried out by known methods such as interfap0|y m-phny|eneis0 cial polycondensation but preferably by solution polyphthglale I h S 9 5% 4.5 condensation in polar organic solvents such as lfLN- mff fi 9v m2 dialltylcarboxylic acid amldes, preferably N,N-d1mewith 20 thylacetamide, or N-alkyl-substituted lactams, preferahydaflwm \mlls bly N-methylpyrrolidone, or in tetramethylurea or hex- 40 amethylphosphoric acid triamide, etc. or in mixtures of such polar aprotic solvents, without additional acid ac- Experfmemal method for determmmg the molsmre ceptors but optionally in the presence of solubilizing absorption capacltyi o agents such as alkali metal or alkaline earth metal ha- The fibres are washed at 9 Cr dried and h lides if this is necessary to keep the copolyamides in so- P9 to an atmosphere of 20 C and 65% relanye lurion as they are being f d condensation is can midity for 24 hours to enable them to absorb mmsture. ried out at temperatures of between 30 and +150C, fibres are dried m a Vacuum at andfhe preferably between l0 and +30C. The reaction times molstul'e absorption is measured in Percent by welght may be between 1 and 30 hours. The solids content of of the absoluiely y fibresthe solutions is 5 to 40%, preferably 15 to 25%. In The threads y in p p be Produced y any of order to obtain very high molecular weight reaction the u al methods of dry spinning or wet spinning. The products, it is advisable to use equimolar amounts of p g 5011100118 used e e preferably polyamide sothe diamine component (both diamines) and dicarboxin dlmethylacemmide N-mCthYIPYTYOhdOHe ylic acid dichloride component although in principle Which had a polyamide Solids 60mm! of between 15 the polycondensation ay also b arri d o t ith an and 25%. The concentration of solubilizing agent used excess or subequivalent quantity of dicarboxylic acid q which was preferably CaClz Licl, was dichloride. The dicarboxylic acid dichloride may be between 3 and 12%- The V SoOSitieS 0f the spinning added in several small portions distributed over a per- Solutions were preferably between 400 and 1100 poises iod of time to the solution or suspension of the di- (measured at 20C in arotation viscosimeter) although amines in the solvent. in some cases, however, it is adsolutions having viscosities of up to 2000 poises can be visable to add the dicarboxylic acid dichloride all at spun quite easily. The relative viscosity Th of the once and preferably with cooling. copolyamide was between 1.3 and 2.5 but mainly be- The hydantoin copolyamides according to the inventween 1.4 and 1:8 (measured on a 0.5% solution in contion have good thermal and mechanical properties. centrated sulphuric acid at 20C). They can easily be worked up and used for the manu- When the wet spinning process was employed, the facture of films, foils, threads and bristles which have threads were coagulated in an aqueous precipitation excellent thermal and mechanical properties. bath at 50 to 60C and drawn off at the rate of 10 to 15 m/min from a 10 aperture die (diameter of apertures 0.1 mm). In the case of the dry spinning process, the spinning solution, which was kept at a temperature of 40C, was extruded through a 72 or 144 aperture die (diameter of apertures 0.1 mm) into a spinning shaft heated to about 200C with hot air, and the thread produced was drawn off at the rate of 100 m/min.

An aftertreatment is essential for the production of threads which have good textile properties. Both wet spun and dry spun threads are advantageously first prestretched to a ratio of between 1 1.2 and 1 1.5 in boiling water and then washed in water at 60C and dried. The final stretching is then carried out to a stretching ratio of between 1 z 2 and l 5 at a temperature of 300 to 350C.

The ultimate tensile strengths of the stretched threads were between 1.5 and 5.3 g/dtex.

The following Examples are to further illustrate the invention without limiting it.

EXAMPLE 1 98.3 Parts by weight of m-phenylene diamine'and 27.9 parts by weight of l,3-bis-(p-aminopheny1)-5,5- dimethyl-hydantoin (9 mols based on the total quantity of diamine) were introduced into 1000 parts by weight of absolute N-methyl pyrrolidone. The mixture was then cooled to about 3 0C. 203 Parts by weight of isophthalic acid dichloride were added in one portion and the viscous solution then stirred for several hours at room temperature. The hydrochloric acid formed in the process of condensation was neutralised by the addition of 74.1 parts by weight of calcium hydroxide.

This solution was spun wet through a 10 aperture die with an aperture diameter of 0.1 mm into an aqueous precipitation bath at 30 to 40C. The threads were drawn off at the rate of 10 to m/min. They were then subjected to a two-stage stretching process in which they were first stretched in the ratio of 1 1.5 in boiling water and then, after being washed in water at 60C, they were finally stretched at a ratio of l 3.5 at 350C. The ultimate tensile strength of the stretched threads was 2.7 to 3.0 g/dtex at an elongation of 10%. The moisture absorption capacity was determined as follows: The fibres were washed at 30C, rapidly dried and then exposed to an atmosphere of C and 40% relative humidity for moisture absorption. The fibres are then dried in a vacuum at 80C. The moisture absorption, given in percent by weight of the absolutely dry fibres, was 9.8%.

EXAMPLE IA This Example shows that preparation of the copolymer described in Example 1 which consists predominantly of poly-m-phenylene isophthalarnide may advantageously be carried out using 3',5 "-diamino-isophthalic acid anilide of the following formula NHOC COHN NH instead of m-phenylene diamine without substantial alteration in the water absorption capacity.

EXAMPLES 2 4 Modified poly-m-phenylene isophthalimide was prepared by copolycondensation of 5,6 and 8 mols percent, respectively, of l,3-bis-p-(aminophenyl)-5,5- dimethyl-hydantoin (based on the total quantity of diamine) as described in detail in Example 1. The properties of the stretched threads are summarized in the following table:

Example Proportion Strength Elonga- Moisture of hydantoin in tion absorpdiamine in g/dtex tion in mols% COMPARISON EXAMPLES 2 4 These Examples show that the moisture absorbent capacity of modified poly-m-phenylene isophthalamides which contain 20 -]40 mols percent of units of the following formula -mq- A l tll- -NH--OC is not so high as that of the copolyamides described in Examples 2 to 4. The results of comparison Examples 2 4 are summarized in the following Table:

Compari- Proportion Strength Elonga- Moisture son of hydantoin in tion absorp- Example diamine in gldtex tion in mo1s% q The preparation of the copolyamide containing 30 mo1s% of hydantoin units (Comparison Example 3) is described below by way of example. 60.5 Parts by weight of m-phenylene diamine and 74.4 parts by weight of l,3-bis-(p-aminophenyl)-5,5-dimethylhydantoin (30 mols based on the total quantity of diamine) were introduced into 890 parts by weight of absolute N-methylpyrrolidone. 1624 Parts by weight of isophthalic acid dichloride were then added portionwise at 0 to 5C with constant stirring and the viscous solution then continued to be stirred for several hours at room temperature. Since this copolyamide is soluble in N-methylpyrrolidone. the addition of a solubilizing agent (e.g. CaCl,) is not necessary. The hydrochloric acid formed on condensation may therefore be neutralised with 93 parts by weight of propylene oxide instead of with Ca(OH) The solution is then spun and aftertreated as described in Example 1.

EXAMPLE 5 [02.5 Parts by weight of m-phenylene diamine and 34.8 parts by weight ofthe diamine of the following formula in l020 parts by weight of'N-methylpyrrolidone are reacted with 203 parts by weight of isophthalic acid dichloride as described in Example 1. The hydrochloric acid formed in the reaction was neutralised with 74.1 parts by weight of Ca(OH This solution was spun and aftertreated as described above. The stretched threads have an ultimate tensile strength of 27 and 3 g/dtex and an elongation of Their water absorption capacity is 9.7%.

We claim:

1. High molecular weight aromatic copolyamide consisting essentially of less than mol percent of structural units which contain hydantoin rings of the formula 2 is a single bond or Hy-X;

X and Y, which may be the same or different, are divalent aromatic groups which consist of one or more condensed rings or several aromatic rings which are linked together by single bonds or by bridge members selected from the group consisting of and NHSO,; or the halogen, C, to C alkyl, N0 or CN substitution products of said divalent aromatic group;

Hy is a divalent hydantoin ring of the formula a; //o -N L C II o 12 R is hydrogen, C -C alkyl, cycloalkyl or phenyl; Ar is a divalent aromatic group which contains of one or more condensed rings or of several aromatic rings which are linked together by single bonds or by bridge members selected from the group consisting of members-O,S,SO,,

9% o CH30-C/ or the halogen, C to C alkyl, N0 and CN substitution products of said divalent aromatic group; and more than 85 mol percent of structural units of the formula HNAr'-NH-OC-ArCO (II) in which Ar has the meaning indicated above; and Ar has the meaning indicated for X; the copolyamides having a relative solution viscosity 1; (measured on a 0.5% solution of the copolyamide in concentrated sulphuric acid at 25C) of 1.2 2.5; the copolyamides containing a mol percent of hydantoin units sufficient to achieve a moisture absorption of at least 9% in a fiber prepared therefrom in which moisture absorption is measured by comparing moist fiber prepared by washing the fiber at 30C., drying, exposure to an atmosphere of 20C. and 65% relative humitity for 24 hours; and dry fiber dried in a vacuum at C. 2. High molecular weight aromatic copolyamide of claim 1, XHyYZ in Formula I is CH 3 /O 3. High molecular weight aromatic copolyamide of claim 1, in which Ar is mor p-phenylene.

4. High molecular weight aromatic polyamide of claim 1, in which Ar in the formulae l and ll is mor p-phenylene.

5. High molecular weight aromatic polyamide of claim 1, in which Ar in the general formulae l and ll is 6. A fiber prepared from the high molecular weigh copolyamide of claim 1.

7. High molecular weight copolyamide of claim 1 in which said structural units containing hydantoin rings comprise 5-l2 mol percent of said copolyamide.

8. High molecular weight copolyamide of claim 1 in which said structural units containing hydantoin rings comprise 5-9.5 mol percent of said copolyamide.

9. High molecular weight copolyamide of claim I which contains a degree of crystallinity characteristic of the corresponding polyamide without hydantoin units which crystallinity is detectable by X-ray wide angle diffraction.

10. High molecular weight copolyamide of claim 1 in which X and Y are the same or different and are phenylene, substituted phenylene, or more than one phenylene or substituted phenylene linked together by single bonds or by bridge members selected from the group consisting of and NH-SO wherein said substituted phenylene is substituted with halogen, C to C -alkyl, N0 or CN; and

Ar is naphthylene, phenylene, substituted phenylene,

or more than one phenylene or substituted phenylene linked together by single bonds or by bridge wherein said substituted phenylene is as defined above. 

1. HIGH MOLECULAR WEIGHT AROMATIC COPOLAMIDE CONSISTING ESSENTIALLY OF LESS THAN 15 MOL PERCENT OF STRUCTURAL UNITS WHICH CONTAIN HYDANTOIN RINGS OF THE FORMULA
 2. High molecular weight aromatic copolyamide of claim 1, X-Hy-Y-Z- in Formula I is
 3. High molecular weight aromatic copolyamide of claim 1, in which Ar'' is m- or p-phenylene.
 4. High molecular weight aromatic polyamide of claim 1, in which Ar in the formulae I and II is m- or p-phenylene.
 5. High molecular weight aromatic polyamide of claim 1, in which Ar in the general formulae I and II is
 6. A fiber prepared from the high molecular weight copolyamide of claim
 1. 7. High molecular weight copolyamide of claim 1 in which said structural units containing hydantoin rings comprise 5-12 mol percent of said copolyamide.
 8. High molecular weight copolyamide of claim 1 in which said structural units containing hydantoin rings comprise 5-9.5 mol percent of said copolyamide.
 9. High molecular weight copolyamide of claim 1 which contains a degree of crystallinity characteristic of the corresponding polyamide without hydantoin units which crystallinity is detectable by X-ray wide angle diffraction.
 10. High molecular weight copolyamide of claim 1 in which X and Y are the same or different and are phenylene, substituted phenylene, or more than one phenylene or substituted phenylene linked together by single bonds or by bridge members selected from the group consisting of -O-, -S-, -SO-2, 